Roller leveler with adjustable flattening section

ABSTRACT

A vertically spaced pair of roll units, constituting a shape correction section, extend lengthwise between the bed and vertically adjustable beam of a roller leveler. One of these roll units is supported by the beam. There is a second vertically spaced pair of roll units that form a flattening section beside the shape correction section. The side of one of the flattening roll units nearest the other section is pivotally connected to the beam on an axis extending lengthwise of it. There also are vertically adjustable means, located between the pivot and the opposite side of the pivoted roll unit, which connect the latter to the beam in a manner that permits the roll unit to be tilted transversely. Means are provided for moving the pivot vertically relative to the beam to enable the pivoted flattening roll unit to be adjusted vertically relative to the shape correction roll unit beside it. Means also may be provided for deflecting the other flattening roll unit relative to the shape correction section.

- United States Patent Roesch ROLLER LEVELER WITH ADJUSTABLE FLATTENING SECTION [451 Oct. 31, 1972 [57] ABSTRACT A vertically spaced pair of roll units, constituting a shape correction section, extend lengthwise between the bed and vertically adjustable beam of a roller leveler. One of these roll units is supported by the beam. There is a second vertically spaced pair of roll units that form a flattening section beside the shape correction section. The side of one of the flattening roll units nearest the other section is pivotally connected to the beam on an axis extending lengthwise of it. There also are vertically adjustable means, located between the pivot and the opposite side of the pivoted roll unit, which connect the latter to the beam in a manner that permits the roll unit to be tilted transversely. Means are provided for moving the pivot vertically relative to the beam to enable the pivoted flattening roll unit to be adjusted vertically relative to the shape correction roll unit beside it. Means also may be provided for deflecting the other flattening roll unit relative to the shape correction section.

11 Claims, 8 Drawing Figures minimum 31 m2 SHEET 2 OF 5 NOE INVENTOR CH/Q/ST/A/V #055677 PATENTED am 3 1 m2 SHEET 3 BF 5 R O N E V m CHR/SWA/V 05501 ATTORNEYS.

PKTENTED 0m 3 1 1912 SHEET U 0F 5 IN V EN TOR (HQ/SWAN 05509 ATTORA/EVS.

ROLLER LEVELER WITH ADJUSTABLE FLATTENING SECTION Many roller levelers have a flattening or exit tilt section and a shape correction section that are separate from each other but adjustable vertically in unison to change the basic wave depth control of the material traveling through the leveler. The upper roll unit of the flattening section can be tilted transversely to reduce the wave depth as the material leaves the leveler. In the past, when the screwdowns were operated, both the shape correction and the flattening sections had to be adjusted vertically to the same extent.

It is among the objects of this invention to provide a roller leveler in which the wave depth at the entry side of the flattening section can be varied relative to the wave depth of the shape correction section, in which one roll unit of the flattening section can be tilted relative to the shape correction section, in which one roll unit of the flattening section can be adjusted vertically relative to the shape correction section, and in which the other roll unit of the flattening section can be deflected relative to the shape correction section.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which FIG. 1 is a front view of the roller leveler;

FIG. 2 is a view of the left-hand side;

FIG. 3 is an enlarged fragmentary view from the right-hand side of the leveler, with the end frames omitted and with parts broken away in section;

FIG. 4 is an enlarged vertical section taken approximately on the line IVIV of FIG. 2;

FIG. 5 is a vertical section, similar to FIG. 4, of a modification;

FIG. 6 is an enlarged fragmentary elevation taken on the line Vl-VI of FIG. 5;

FIG. 7 is a horizontal section taken on the line VII VII of FIG. 6; and

FIG. 8 is an enlarged fragmentary detail of the tilt plate suspension.

Referring to FIGS. 1 to 4 of the drawings, the lower portions of a pair of front and rear end frames 1 and 2 of a roller leveler housing are connected by a long bed 3. Extending between the upper portions of the end frames and across their tops is a top beam 4 that can be adjusted up and down by screwdowns 5 at the upper corners of the housing. In the entry half of the housing, at the right-hand side as viewed from the front, there is a pair of vertically spaced roll units 6 and 7 that extend lengthwise of the housing in the space between its bed and the top beam. They constitute the shape correction section of the leveler. In the exit half of the housing there is another pair of vertically spaced roll units 8 and 9, which form the flattening section.

Referring to the first pair of roll units, the upper unit 6 includes several work rolls 11, the ends of which are journalled in bearing blocks 12 that are held in retaining blocks 13 by vertical screws 14, as shown in FIG. 1. These rolls can be turned by the product pulled through the leveler, or they can be driven from their rear ends. The tops of the two retainers are provided 1 with laterally projecting tongues 15 which are supported by gibs 16, bolted to cross members 17 that in turn are fastened to the top beam. Intermediate rolls 18 may be provided which rest on the work rolls. As shown in FIGS. 2 and 3, their ends engage thrust rollers 19 supported on vertical axes by brackets 20 bolted across the inner faces of the retainers.

- cross members 17 and are secured to the bottom of the top beam, so the bearing block retainers and the backup roll supports are all hung from the top beam. The grooves 25 line up with the grooves formed by the front and rear gibs 16. The outer sides of the roll supports bear against vertical thrust plates 27 fastened to the side of the top beam and extending below it.

The front and rear bearing block retainers 13 and the back-up roll supports 23 are tied together to form the unit 6 by means of an elongated member secured to them and extending lengthwise of the housing. Preferably, this member is a carrying plate 30 that extends through a central slot 31 in the top of each retainer and aligned slots in the tops of the roll supports 23. The plate is bolted to the tops of the retainers and to the roll supports. The roll unit just described can be held in operating position in the housing in simple manner by bolts 35 (FIG. 1) extending up through the projecting ends of the carrying plate into cross members 17, or by clamping the gibs tightly against the tongues on the bearing block retainers, or by both. Whatever the fastening means used, when they are released the entire roll unit can he slid bodily lengthwise out of the housing through front end frames 1, due to the tongue and groove connections between the roll unit and the housing, and onto a suitable support by which the unit can be carried away from the housing. By reversing the process, a roll unit can be quickly slid into the housing and quickly fastened in place.

The lower roll unit 7 is, in general, the same as the upper unit. The bearing blocks 39 for the work rolls 40, however, are pivoted on horizontal pins 41 anchored in tilt blocks 42 fastened in retainers 43, so that the bearings can tilt slightly if the work rolls are deflected vertically out of a straight line. As shown in FIG. 1, the bottoms of the retainers have laterally projecting tongues 44 that project into grooves formed by gibs 45 bolted to base blocks 46 secured to the top of the bed of the housing. When a group of intermediate rolls 47 are used, their ends engage thrust rollers 48 supported on vertical axes by brackets 49 extending across the inner faces of the retainers and secured thereto.

Engaging the intermediate rolls are back-up rolls 50 that are journalled in supports 51 like those in the upper roll unit. They engage vertical thrust plates 52 secured to the side of the housing bed and projecting above it. These lower roll supports are intended to be adjusted vertically to permit the work rolls to be deflected when necessary in order to properly process the strip or sheet passing through the leveler. For this purpose, each back-up roll support is mounted on deflecting apparatus. Each deflector includes a rocker block 53 provided at the top with grooves extending lengthwise of the housing that receive laterally projecting tongues 54 on the bottom of the overlying roll support. In its lowest position, the rocker block may rest flat on the bed of the machine. It is urged toward this position by gravity and by lugs 56 projecting into slots 57 in the sides of the block. The lugs are integral portions of cup-like members 58, through which extends studs 59 that are threaded in the housing bed. A coil spring 60 on each stud is compressed between its head and the bottom of the cup to press the cup downwardly.

Each rocker block 53 is provided in its bottom with a concave recess 62 that extends transversely across it. Fitting in this recess is a convex wedge block 63 (FIGS. 3 and 4) provided with a longitudinal wedge slot 64 that is open at the bottom. The upper wall of the slot is flat and inclined from end to end. A wedge 65 is disposed in the slot and bears against the inclined wall and the underlying housing bed. The outer end of the wedge block overlaps the side of the housing bed slightly and also engages a thrust plate 52 to prevent endwise movement of the block.

Threaded in each wedge is a screw 66, the outer end of which extends through the thrust plate as shown in FIG. 4 and is provided with a collar 67 rotatably mounted in a bearing 68 fastened to the thrust plate to prevent movement of the screw lengthwise. The screw can be turned when desired by an electric motor 69 geared to it and supported by a bracket 70 projecting from the thrust plate. When the wedge is driven inwardly by the screw, it will raise the wedge block and the rocker block above it in order to lift the back-up roll support 51 and thereby flex the work rolls upwardly at that point in a well-known manner.

In order to complete roll unit 7, an elongated member ties retainers 43 and roll supports 51 together. Here again this member preferably is a carrying plate 72 that extends through downwardly opening slots 73 and 74 in the bottoms of the retainers and roll supports, respectively. As shown in FIG. 3, the ends of the carrying plate are loosely bolted to the retainers. The plate is also loosely bolted to the roll supports.

Lower roll unit 7 can be held in operating position in the same way as upper unit 6, by bolts 78 extending down through the projecting ends of the plate into the front and rear base blocks 46, or gibs 45 can be tightened down on tongues 44 to clamp the unit in place, or both systems can be used. In any event, the unit can be released quickly and moved lengthwise out of the front of the housing onto a suitable support, by which it can be carried away.

The screwdowns at the corners of the housing are described in detail in the copending patent application, Ser. No. 6,749, filed Jan. 29, 1970 by Elbert G. Thompson and Max F. Alters. The screwdowns adjust the top beam 4 up and down to vary the spacing between the upper and lower roll units 6 and 7.

The other pair of roll units 8 and 9 are similar to the first pair that has been described. The work rolls 80 (FIG. 2) of the lower roll unit 9 are journalled in bearing blocks 81 that are held in retaining blocks 82. The bottoms of the retainers have laterally projecting tongues 83 that project into grooves formed by gibs 84 bolted to base blocks 85 secured to the top of the housing bed. Intermediate rolls 86 are disposed between the work rolls and back-up rolls 87 that are journalled in supports 88 like supports 51 in the deflecting section. Supports 88 engage vertical thrust plates 89 secured to the exit side of the housing bed. They also engage roll supports 51 beside them. Retaining blocks 82 and roll supports 88 are connected by a carrying plate 90 that extends through slots in their bottoms and that is bolted at its opposite ends to base blocks 85.

The upper roll unit 8 includes several work rolls 92, the ends of which are journalled in bearing blocks 93 bolted in retaining blocks 94. The tops of the two retainers are provided with laterally projecting tongues 96 supported by rails 97 secured to the bottom of a heavy tilt plate 98. Intermediate rolls 99 rest on the work rolls and are engaged by a plurality of groups of back-up rolls 100 mounted in bearing supports 101. The top of each support has laterally projecting tongues 102 supported by rails 97. Consequently, the hearing block retainers and the back-up roll supports are all hung from the tilt plate. The retainers and supports are connected to a carrying plate 103 bolted at its ends to the tilt plate. The curved outer sides of the roll supports bear against vertical thrust plates 104 fastened to the side of the top beam. The curved inner sides of the roll supports engage the adjoining roll supports 23 of the deflecting section.

The tilt plate 98 is supported from the top beam by a longitudinal shaft 106 and a vertical plate 107 likewise extending lengthwise of the beam. The shaft is located between the bottom of the beam and the side of the tilt plate adjacent the deflecting section of the leveler. The shaft extends through bearings extending downwardly from the beam and upwardly from the tilt plate.

The vertical plate 107 extends through a slot 108 in the bottom of the hollow top beam. The bottom of the plate is connected to brackets 109 extending upwardly from the tilt plate by means of pins 1 10 that have spherical bearing portions mounted in the vertical plate. The upper portion of the plate inside the top beam is provided with a pair of openings, in each of which there is an eccentric 112. Each eccentric is rigidly mounted on the inner end of a short shaft 113 that is journalled in a bearing 114 in the side of the beam. Rigidly mounted on the outer ends of the two shafts are worm gears 1 16 that mesh with worms 117 on a shaft 118 extending lengthwise of the beam. The ends of this shaft are journalled in gear housings 119 extending downwardly from an overhanging portion of the top beam 4. The central portion of the shaft carries a worm gear 121 that meshes with a worm 122 driven by an electric motor 123 secured to the side of the beam. Consequently, when the motor is operated the eccentrics are turned to raise or lower vertical plate 107 which thereby tilts the tilt plate around its shaft 106.

It will be seen that when the screwdowns are operated the top beam will be moved up or down and will carry with it the upper roll units 6 and 8 suspended from it. This will change the wave depth of any metal strip traveling through the leveler. Also, by operating motor 123 the outer side of the upper roll unit of the flattening section can be tilted upwardly to progressively reduce the wave depth as the strip leaves the leveler. It is a feature of this invention that for any given vertical position of the top beam, the upper roll unit of the flattening section can be raised or lowered bodily relative to the beam and to the roll unit 6 beside it.

Accordingly, a number of eccentrics 125 are mounted on shaft 106 above the tilt plate and they are rotatable in some of the shaft bearings 126 or 127 preferably those attached to the tilt plate. Consequently, when the shaft is turned while the top beam is stationary, the eccentrics will raise or lower the entry side of the upper roll unit of the flattening section. This allows any desired adjustment of the shape correction section to be made by means of the screwdowns, and then the flattening section can be further adjusted vertically as well as tilted. A convenient way of turning shaft 106 is to mount a worm gear 128 on its front end in mesh with a worm 129 on a stub shaft 130 journalled in a gear case 131 attached to the bottom of the top beam. One end of the stub shaft is formed for turning by a suitable tool or the like in order to turn the main shaft 106. It will be seen that with this construction the upper roll unit 8 of the flattening section can be raised or lowered while the screwdowns are motionless, and it also can be tilted.

Another way of accomplishing this desirable result is illustrated in FIGS. 5 to 8. Parts that are the same in FIG. 5 as in FIG. 4 are numbered the same. A heavy tilt plate 135, whichsupports bearing supports 101 for the back-up rolls, is suspended at its left-hand side by a vertical plate 107 extending lengthwise of the top beam 4. The bottom of the plate is connected to brackets 109 by means of pins 136 that extend through ball joints 137 mounted in the vertical plate as shown in FIG. 8. The plate can be adjusted vertically relative to the beam by means of eccentrics rigidly mounted on the inner ends of short shafts 113 journalled in the side of the top beam and rotated by an electric motor 123.

Unlike tilt plate 98 in FIG. 4, the right-hand side of plate 135 is supported by a second vertical plate 139 likewise extending lengthwise of the top beam. The bottom of the vertical plate is provided with ball joints 140 (FIG. 8), through which pins 136 also extend as well as through brackets 141 projecting upwardly from the top of the tilt plate. Ball joints 137 and 140 are located directly above the inner and outer work rolls 92. The upper part of vertical plate 139 is provided with longitudinally spaced rectangular openings 142 as shown in FIGS. 6 and 7, in each of which there is a slide block 143 held in the plate by gibs 144. Rotatably mounted in the slide block is a spherical bearing 145 that is mounted on an eccentric extension 146 of a horizontal shaft 147 journalled in the top beam and extending out through the side of the beam at the entry side of the leveler. The outer end of this shaft is operatively connected to an electric motor 148 secured to the top beam. When shafts 147 are turned, they will raise or lower vertical plate 139 relative to the beam and plate 107, thereby producing the same effect as turning eccentric shaft 106 in FIG. 4. That is, wave depth adjustment is around ball joints 137 as pivots, while tilt adjustment is around ball joints 140 as pivots. Each adjustment is independent of the other. The ends of the vertical plate slide on guide surfaces 149 on end frames 1 and 2. Lugs 150 projecting inwardly from thrust plates 104 and inner track bar 26 prevent the tilt plate from shifting sideways unduly.

FIG. 5 also shows that the lower work rolls 80 can be deflected in the same general manner as lower work rolls 40. This is done by wedges 152 disposed in slots in the bottom of wedge blocks 153 mounted in rocker blocks 154 which support the lower back-up roll supports 88. The wedges are adjusted by screws 155, the outer ends of which are turned by gears in gear boxes 156 supported by lower thrust plates 89. Each gear box is connected by a chain and sprocket drive 157 to a shaft 158 extending along the side of the leveler and supported in bearings 159. This shaft can be turned by a hand wheel or other suitable device to rotate all of the wedge screws simultaneously.

The three independent adjustments provided in the flattening section, namely, entry wave depth, tilt and roll deflection, enable the operator to obtain a better leveled product than was possible heretofore.

According to the provisions of the patent statutes, 1 have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A roller leveler comprising a housing having end frames at the opposite ends of a vertically spaced bed and beam, means for adjusting said beam vertically, a first vertically spaced pair of roll units extending lengthwise between said bed and beam and constituting a shape correction section of the leveler, meanssupporting one of said roll units by said beam for movement with it, a secondvertically spaced pair of roll units between said bed and beam beside said shape correction section and constituting a flattening section of the leveler, means pivotally connecting the side of a flattening roll unit adjacent said shape correction roll unit with said beam on an axis extending lengthwise thereof, vertically adjustable means between said pivotal means and the opposite side of the pivoted roll unit connecting the latter to the beam to permit the roll unit to be tilted transversely, and means for adjusting said pivotal means vertically relative to the beam, whereby said pivoted roll unit can be adjusted vertically relative to said shape correction unit.

2. A roller leveler according to claim 1, in which said last-mentioned means include a shaft extending lengthwise of said beam, eccentrics rigidly mounted on the shaft, means encircling the eccentrics and shaft and connecting them with said beam and pivoted roll unit, and means for turning the shaft.

3. A roller leveler according to claim 2, in which said shaft-turning means include a gear rigidly mounted on said shaft, a stub shaft extending laterally of the other shaft and rotatably supported by the beam, and a gear rigidly mounted in the stub shaft and meshing with the other gear for turning it when the stub shaft is turned.

4. A roller leveler according to claim 1, in which said last-mentioned means include a shaft extending lengthwise of said beam, eccentrics rigidly mounted on the shaft, a row of bearings for the shaft, another row of bearings for the eccentrics, one of said rows being secured to the beam and the other row being secured to the pivoted roll unit, and means for turning said shaft to rotate the eccentrics.

5. A roller leveler according to claim 1, in which said beam is above said shape correction and flattening sections, first and second upper roll units of said sections are suspended from the beam, and the second roll unit is the pivoted unit.

6. A roller leveler according to claim 1, in which said first-mentioned vertically adjustable means include suspension means extending vertically above said second upper roll unit, rotatable eccentric means carried by the beam and supporting the upper part of said suspension means, and means for rotating said eccentric means to raise and lower the suspension means.

7. A roller leveler according to claim 6, in which said top beam is hollow and provided with an opening in its bottom, said suspension means is a vertical plate extending through said opening and provided with longitudinally spaced openings inside the top beam, and said eccentric means include rotatable eccentrics mounted in said plate openings, horizontal shafts journalled in the side of the beam and supporting the eccentrics, and means carried by the outside of the beam for turning said shafts to rotate the eccentrics.

8. A roller leveler according to claim 1, in which said last-mentioned means include a shaft extending lengthwise of said beam, eccentrics rigidly mounted on the shaft, means encircling the eccentrics and shaft and connecting them with said beam and second upper roll unit, and means for turning the shaft, said top beam being hollow and provided with an opening in its bottom, and said first-mentioned vertically adjustable means including suspension means extending vertically through said beam opening and attached to said second upperroll unit, rotatable eccentric means carried by the beam and supporting the upper part of said suspension means, and means for rotating said eccentric means to raise and lower the suspension means.

9. A roller leveler according to claim 1, in which said last-mentioned vertically adjustable means include suspension means extending vertically above said second upper roll unit, rotatable eccentric means carried by the beam and supporting the upper part of said suspension means, and means for rotating said eccentric means to raise and lower the suspension means, said pivotal means being carried by the lower part of said suspension means.

10. A roller leveler according to claim 1', in which said vertically adjustable means include parallel vertical plates above said second upper roll unit and extending lengthwise thereof, rotatable eccentric means carried by the beam and supporting the upper parts of said plates, means for rotating the eccentric means of each plate independently of the other to raise and lower the plates, and means pivotally connecting said opposite side of the second upper roll unit with the lower part of one of said plates, said first-mentioned pivotal means being carried by the lower part of the other plate.

11. In a roller leveler having a vertically spaced pair of shape correction roll units and a separate vertically spaced pair of flattening roll units, each of said units including a plurality of parallel work rolls, means for varying the distance between the upper and lower flattening roll units, and means for tilting one of the flattening roll units transversely; means independent of said first and second mentioned means for opening and closing the gap between the pair of upper and lower work rolls at the entry side of the flattening roll units. 

1. A roller leveler comprising a housing having end frames at the opposite ends of a vertically spaced bed and beam, means for adjusting said beam vertically, a first verticAlly spaced pair of roll units extending lengthwise between said bed and beam and constituting a shape correction section of the leveler, means supporting one of said roll units by said beam for movement with it, a second vertically spaced pair of roll units between said bed and beam beside said shape correction section and constituting a flattening section of the leveler, means pivotally connecting the side of a flattening roll unit adjacent said shape correction roll unit with said beam on an axis extending lengthwise thereof, vertically adjustable means between said pivotal means and the opposite side of the pivoted roll unit connecting the latter to the beam to permit the roll unit to be tilted transversely, and means for adjusting said pivotal means vertically relative to the beam, whereby said pivoted roll unit can be adjusted vertically relative to said shape correction unit.
 2. A roller leveler according to claim 1, in which said last-mentioned means include a shaft extending lengthwise of said beam, eccentrics rigidly mounted on the shaft, means encircling the eccentrics and shaft and connecting them with said beam and pivoted roll unit, and means for turning the shaft.
 3. A roller leveler according to claim 2, in which said shaft-turning means include a gear rigidly mounted on said shaft, a stub shaft extending laterally of the other shaft and rotatably supported by the beam, and a gear rigidly mounted in the stub shaft and meshing with the other gear for turning it when the stub shaft is turned.
 4. A roller leveler according to claim 1, in which said last-mentioned means include a shaft extending lengthwise of said beam, eccentrics rigidly mounted on the shaft, a row of bearings for the shaft, another row of bearings for the eccentrics, one of said rows being secured to the beam and the other row being secured to the pivoted roll unit, and means for turning said shaft to rotate the eccentrics.
 5. A roller leveler according to claim 1, in which said beam is above said shape correction and flattening sections, first and second upper roll units of said sections are suspended from the beam, and the second roll unit is the pivoted unit.
 6. A roller leveler according to claim 1, in which said first-mentioned vertically adjustable means include suspension means extending vertically above said second upper roll unit, rotatable eccentric means carried by the beam and supporting the upper part of said suspension means, and means for rotating said eccentric means to raise and lower the suspension means.
 7. A roller leveler according to claim 6, in which said top beam is hollow and provided with an opening in its bottom, said suspension means is a vertical plate extending through said opening and provided with longitudinally spaced openings inside the top beam, and said eccentric means include rotatable eccentrics mounted in said plate openings, horizontal shafts journalled in the side of the beam and supporting the eccentrics, and means carried by the outside of the beam for turning said shafts to rotate the eccentrics.
 8. A roller leveler according to claim 1, in which said last-mentioned means include a shaft extending lengthwise of said beam, eccentrics rigidly mounted on the shaft, means encircling the eccentrics and shaft and connecting them with said beam and second upper roll unit, and means for turning the shaft, said top beam being hollow and provided with an opening in its bottom, and said first-mentioned vertically adjustable means including suspension means extending vertically through said beam opening and attached to said second upper roll unit, rotatable eccentric means carried by the beam and supporting the upper part of said suspension means, and means for rotating said eccentric means to raise and lower the suspension means.
 9. A roller leveler according to claim 1, in which said last-mentioned vertically adjustable means include suspension means extending vertically above said second upper roll unit, rotatable eccentric means carried by thE beam and supporting the upper part of said suspension means, and means for rotating said eccentric means to raise and lower the suspension means, said pivotal means being carried by the lower part of said suspension means.
 10. A roller leveler according to claim 1, in which said vertically adjustable means include parallel vertical plates above said second upper roll unit and extending lengthwise thereof, rotatable eccentric means carried by the beam and supporting the upper parts of said plates, means for rotating the eccentric means of each plate independently of the other to raise and lower the plates, and means pivotally connecting said opposite side of the second upper roll unit with the lower part of one of said plates, said first-mentioned pivotal means being carried by the lower part of the other plate.
 11. In a roller leveler having a vertically spaced pair of shape correction roll units and a separate vertically spaced pair of flattening roll units, each of said units including a plurality of parallel work rolls, means for varying the distance between the upper and lower flattening roll units, and means for tilting one of the flattening roll units transversely; means independent of said first and second mentioned means for opening and closing the gap between the pair of upper and lower work rolls at the entry side of the flattening roll units. 